Interlayer Potential for Graphene/<i>h</i>‑BN Heterostructures

We present a new force-field potential that describes the interlayer interactions in heterojunctions based on graphene and hexagonal boron nitride (<i>h</i>-BN). The potential consists of a long-range attractive term and a short-range anisotropic repulsive term. Its parameters are calibrated against reference binding and sliding energy profiles for a set of finite dimer systems and the periodic graphene/<i>h</i>-BN bilayer, obtained from density functional theory using a screened-exchange hybrid functional augmented by a many-body dispersion treatment of long-range correlation. Transferability of the parametrization is demonstrated by considering the binding energy of bulk graphene/<i>h</i>-BN alternating stacks. Benchmark calculations for the superlattice formed when relaxing the supported periodic heterogeneous bilayer provide good agreement with both experimental results and previous computational studies. For a free-standing bilayer we predict a highly corrugated relaxed structure. This, in turn, is expected to strongly alter the physical properties of the underlying monolayers. Our results demonstrate the potential of the developed force-field to model the structural, mechanical, tribological, and dynamic properties of layered heterostructures based on graphene and <i>h</i>-BN

Interlayer Potential for Homogeneous Graphene and Hexagonal Boron Nitride Systems: Reparametrization for Many-Body Dispersion Effects

A new parametrization of the anisotropic interlayer potential for hexagonal boron nitride (<i>h</i>-BN ILP) is presented. The force-field is benchmarked against density functional theory calculations of several dimer systems within the Heyd-Scuseria-Ernzerhof hybrid density functional approximation, corrected for many-body dispersion effects. The latter, more advanced method for treating dispersion, is known to produce binding energies nearly twice as small as those obtained with pairwise correction schemes, used for an earlier ILP parametrization. The new parametrization yields good agreement with the reference calculations to within ∼1 and ∼0.5 meV/atom for binding and sliding energies, respectively. For completeness, we present a complementary parameter set for homogeneous graphitic systems. Together with our previously suggested ILP parametrization for the heterogeneous graphene/<i>h</i>-BN junction, this provides a powerful tool for consistent simulation of the structural, mechanical, tribological, and heat transport properties of both homogeneous and heterogeneous layered structures based on graphene and <i>h</i>-BN